Sofa



FIG. 1 is an upper perspective view of the sofa showing my design.

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right side view thereof; and,

FIG. 5 is a back view thereof. 

I claim the ornamental design for a sofa, as shown and described. 